1. Field of the Invention
The present invention relates to a gas turbine engine with a seal assembly, and more particularly, to a gas turbine engine having an interstage seal assembly which includes a heat shield member for restraining heat transfer from the high-temperature turbine section to the low-temperature compressor section of the engine and a seal member for limiting the fluid flow between the compressor section and the turbine section.
2. Description of the Related Art
A gas turbine engine refers typically to a type of turbine engine that operates in a Brayton cycle, one of the ideal and basic thermodynamic cycles, and continuously obtains power through compression and subsequent expansion processes of a gaseous working fluid. The gas turbine engine generally requires a small amount of lubricating oil, and enables high-speed driving, and can be small-sized and highly integrated. For these advantages, the gas turbine engine is often used for a power unit for an aircraft and also increasingly applied to ships and industrial equipments. In recent years, the gas turbine engine has been employed in a turbo charger for supplying compressed air, for example, to fuel cell vehicles.
FIG. 1 is a schematic diagram of a conventional gas turbine engine with arrows indicating a direction of air flow in the gas turbine engine.
Referring to FIG. 1, a compressor section 10 of gas turbine engine 1 ingests ambient air, compresses the air, and delivers the compressed air to a combustor section 20. A flow of fuel is supplied to the compressed air in the combustor section 20. Combustion of the fuel maintained within the combustor section 20 provides a flow of high-temperature combustion gas. The high-temperature combustion gas flows to a turbine section 30 wherein it expands and discharges axially to produce power. The turbine section 30 drives a rotor shaft 50, and simultaneously drives the compressor section 10 which is in turn connected to the shaft 50.
Generally, in the gas turbine engine 1, the compressor section 10 and the turbine section 30 are closely located opposing each other so as to minimize the size of the engine. Between the turbine section 30 and the compressor section 10, a seal assembly 40 is disposed to prevent a direct flow of compressed air from the compressor section 10 to the turbine section 30 and also to shield heat transfer from the high-temperature turbine section 30 to the low-temperature compressor section 10.
An example of such a seal assembly is disclosed in U.S. Pat. No. 5,161,945 assigned to Allied Signal Inc., New Jersey. The seal assembly of this disclosure includes a spring member, a seal member, a heat shield member, a shroud member, and a bracket member, which are sequentially assembled. As disclosed in FIG. 6 of U.S. Pat. No. 5,161,945, the seal assembly includes an annulus formed from a large body of honeycomb material to resist thermal and pressure stresses thereon. In particular, to prevent the seal assembly from being damaged due to high-temperature combustion gases flowing from a turbine section, the heat shield member is installed to face the turbine section of the seal assembly. With reference to FIG. 2 (which is FIG. 8 in U.S. Pat. No. 5,161,945), the heat shield member 92 has a form of an annular plate. However, since a portion of the heat shield member contacting the high-temperature combustion gases has a flat plate shape, a serious thermal buckling can be occurred from a prolonged use of the engine, particularly, by repeatedly exposing to a sharp change in the temperature during the transition operation cycles of the gas turbine engine, thus reducing the life span thereof.